If you’ve traveled by airplane in the past few years, chances are you’ve walked through a full body scanner at the security chec

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问题     If you’ve traveled by airplane in the past few years, chances are you’ve walked through a full body scanner at the security checkpoint.
    The first generation of full body X-ray scanners rolled out in airports across the US in 2008. Known as backsatter scanners, there was a bit of an uproar from consumers when these came on the scene. Fliers feared the imaging would visually strip them of their clothes in front of the Transportation Security Administration (TSA) agents. Some health experts also worried that these models might expose people to unnecessary radiation.
    But in 2013, the TSA replaced backscatter scanners with new-and-improved scanners, called millimeter wave screeners. They fixed the "see you naked"issue. These devices create a standard outline of a person, rather than a detailed image of the person’s body. They’re also an improvement for your health. The millimeter wave scanners use low power radio frequency waves to create the image. The frequency is the same as that used for Wi-Fi devices. If you stood for three seconds in a scanner, it would be no more radiation exposure than standing in front of your computer router at home.
    Backscatter scanners, meanwhile, can still be found in other places like jails and courthouses. They do expose people to small amounts of X-rays, but the Food and Drug Administration (FDA) considers them safe. A person receives more radiation from naturally occurring sources in less than an hour of ordinary living than from one screening with any general-use X-ray security system, says the FDA. Yet others are not so convinced.
    The European Union prohibits the backscatters. Some scientists believe that even very low level X-ray exposure could increase the risk of cancer. " I would agree that the individual risk associated with X-ray scanners is likely to be extremely small," says David Brenner, head of Columbia University’s Center for Radiological Research. "The issue of concern is when the X-ray scanners are used in a very high volume setting (just under a billion security screens occur each year in US airports). A very tiny risk multiplied by a billion has the potential to represent a public health issue. "
David Brenner’s remarks support the idea that________.

选项 A、low level X-ray exposure may become a health concern
B、exposure to X-rays is a common phenomenon in our life
C、tiny risks may develop into big threats to traffic safety
D、the European Union’s ban of backscatters is an overreaction

答案A

解析 细节题。文章最后一段提到,哥伦比亚大学放射学研究中心主任戴维.布伦纳说:“我同意与X射线扫描仪相关的个体风险可能很小。令人担忧的问题是,当X射线扫描仪的使用量很高时(美国机场每年进行十亿次左右的安全检查)。很小的风险乘以十亿就有可能代表一个公共健康问题。”由此可知,戴维.布伦纳的评论支持低水平的X射线暴露可能成为一个健康问题。故选A。
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